As fishing lines for use in fishing, there have conventionally been adopted synthetic resin wires composed of polyamide, polyester, or polyvinylidene fluoride resin, or metal wires composed of piano steel wire, stainless steel wire, or tungsten steel wire. Fundamental characteristics required for such fishing lines include a lower cutwater resistance, a better bite sensitivity, less subaqueous deterioration in the sea and river, and even flexibility. Moreover, the fishing lines are required to have different characteristics depending on the type of fish to be caught as well as on the way of fishing, and according to these characteristic requirements the aforementioned materials are selected. For example, fishing for ayu with a live decoy goes in such a way that the catch is drawn out in a rapidly flowing river approximately the instant the strike occurs, in which case the fishing lines involved are required to have greater tensile strength against impact force in addition to the fundamental characteristics described above. Therefore, the fishing lines for use in fishing are preferably metal wires that have about 1.5 times larger tensile strength than synthetic resin wires as well as smaller wire diameters.
Also, of the above-described fishing lines there has been a desire that such a one be realized as can be improved in tensile strength while being made further thinner in wire diameter, and that still has sufficient flexibility. Examples of such type of fishing line include one disclosed in Japanese Patent Laid-Open Publication No. 62-320472 (JP1-160443). This prior-art fishing line is formed by joining a plurality of amorphous metal wires together into a stranded wire and further coating it with a synthetic resin. This type of fishing line, which employs an amorphous metal, allows its tensile strength to be improved while being made thinner in wire diameter than conventional metal wires such as piano steel wires. Moreover, since the fishing line is structured by stranding together a plurality of solid wires, sufficient flexibility can be ensured.
However, the prior-art amorphous metal wire according to the above-cited patent laid-open publication, although being superior in tensile strength to those conventional metal wires, yet has suffered from lower knot strength for joining two fishing lines together or tying the fishing line to the hook such that the wire is easy to break. To prevent this, there has been adopted a countermeasure that some adhesive is used to bond the wire.
Furthermore, there is another problem in the above conventional fishing lines that they are inferior in their curling characteristic and kink characteristic which matter when some impact force acts thereon.
The curling mentioned above refers to the fact that a fishing line, when pulled into a tensional state with a large load and thereafter abruptly freed therefrom, will be subject to shape change in curls in its longitudinal direction. A large amount of such curls will cause the fishing line to be extended in length and reduced in tensile strength. Therefore, it is of significance to minimize the amount of curls in terms of improving the service life of the fishing line.
The kink mentioned above, in turn, refers to the state in which the curled portions are bent at an acute angle, bringing about a possibility that the fishing line may break. Accordingly, occurrence of kinks can be a critical wound for the fishing line. In consequence, it is important to minimize the occurrence of both curls and kinks with a view to improving the service life of fishing lines.
One method of improving the curling and kink characteristics may be that the fishing line is formed into such a wire diameter as to withstand any impact force; however, in such a case, subaqueous resistance will increase as much as the fishing line gets thicker, so that it can no longer meet the fundamental characteristic for the fishing line.
Accordingly, the object of the present invention is to provide a fishing line which can be improved in their knot strength while satisfying the fundamental characteristics for the fishing line, and yet which is superior in curling characteristic and kink characteristic.